In biology and ecology, extinction is the ceasing of existence of a species. The moment of extinction is generally considered to be the death of the last individual of that species. Extinction is a natural phenomenon; it is estimated that 99.9% of all species that have ever lived are now extinct. Through evolution, new species are created by speciation — where new organisms arise and thrive when they are able to find and exploit an ecological niche — and species become extinct when are no longer able to survive in changing conditions or against superior competition.
Source: Wikipedia |
